1. Field of the Invention
The present invention relates to a novel DNA molecule encoding transglutaminase and the transglutaminase encoded therefrom.
2. Description of the Prior Art
Transglutaminases are Ca2+-dependent enzymes that catalyze the formation of isopeptide bonds in proteins between the side chain gamma-carboxamide group of glutamine and the side chain epsilon-amino group of lysine. The transglutaminases can be used in food processing such as the production of gelatinous, crosslinked gel, the induction of crosslinking of the surface of a fiber bundle and the production of cheese product. The transglutaminases also can be used in the treatment of chronic wound condition and as biological glues.
Transglutaminases have been found both extracellularly and intracellularly. A wide variety of transglutaminases have been identified and characterized from a number of animals and a few plant species. Unfortunately, transglutaminases derived from animals, such as guinea pigs, is impractical for use in industry because it is difficult to obtain a large amount of such animal-derived transglutaminases at low costs. Only few microbial transglutaminases have been disclosed, namely tranglutaminases from the species Streptoverticillium mobaraense, Streptoverticillium cinnamoneum, and Streptoverticillium griseocarneum (in U.S. Pat. No. 5,156,956) and from the species contemplated to be Streptomyces lavendulae (in U.S. Pat. No. 5,252,469). According to Wu et al, the transglutaminases of Streptoverticillium ladakanum has the highest activity among the strains screened (Wu et al., 1996, Chinese Agric. Chem. Soc. 34(2): 228-40).
The genes encoding transglutaminase have been cloned from Streptoverticillium sp. S-8112 (Washizu et al., 1994, Biosci. Biotechnol. Biochem. 58(1): 82-7.), Streptoverticullium cinnamoneum (Pasternack et al., 1998, Eur.J. Biochem. 257(3): 570-6.), Streptomyces lydicus (WO 9,606,931), and Bacillus subtilis (Kobayashi et al., 1998, J. Gen. Appl. Microbiol. 44: 85-91).
Incidentally, current genetic engineering techniques have made it possible to obtain a large amount of an enzyme relative easily. This is achieved by isolating the gene coding for the enzyme, determining the base sequence of the enzyme, producing a recombinant DNA containing the gene coding for the enzyme, incorporating the recombinant DNA into microorganism or animal or plant cells, and cultivating the obtained transformants.
One object of the invention is to provide an isolated and purified DNA molecule comprising a sequence encoding transglutaminase, wherein said nucleic acid hybridizes under highly stringent conditions to the sequence as shown in SEQ ID NO: 1, or the complements thereof.
Another object of the invention is to provide an expression vector comprising the DNA molecule of the invention.
One further object of the invention is to provide a host cell comprising the expression vector of the invention.
Another further object of the invention is to provide a polypeptide comprising the amino acid sequence encoded by the DNA molecule of the invention.